Freezing tray arrangement



March 29, 1955 'AR 2,704,927

FREEZiNG TRAY ARRANGEMENT Filed Aug. 2, 1951 2 Fl I. Z

Inventor: John Rayburn Carrell,

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'3 His Abtor-ne s/ United States Patent FREEZING TRAY ARRANGEMENT JohnR. Carrell, Richland, Wash., assignor to General Electric Company, acorporation of New York Application August 2, 1951, Serial No. 239,871

3 Claims. (Cl. 62-99) My invention relates to household refrigeratorsand, inore particularly, to a freezing tray arrangement there- It iscommon practice in household refrigerators to provide a support withinthe evaporator or freezing compartment for holding a plurality offreezing trays. In the usual case, this support consists of a metalshelf or metal slides projecting from the sides of the compartment so asto furnish an excellent heat conduction path between the walls of thetray and the walls of the evaporator or freezing compartment. In such anarrangement the actual heat transfer involved in the freezing process isaccomplished almost entirely by conduction of heat through the walls ofthe tray. The freezing process within the tray thus proceeds more orless from the side and bottom portions of the block towards the centerand top portions. While this arrangement provides for relatively rapidfreezing, it is subject to the disadvantage that the resulting ice blockadheres to the walls of the tray and is frequently difficult todislodge. In my present invention I provide a new and improvedarrangement for freezing trays whereby this disadvantage of adhesionbetween the ice and the tray is overcome. My invention contemplatessupporting the freezing trays within the evaporator or freezingcompartment in such a manner that the actual freezing process proceedssubstantially from the top or exposed surface of the water toward thebottom portions. In my arrangement the heat transfer necessary forfreezing the water takes place almost entirely by radiation in contrastto the conventional method which utilizes conduction. As a direct resultof my arrangement, the actual freezing process is effective to break theadhesion which tends to occur between the block and the walls of thetray. It is known that when water is transformed into ice, a substantialincrease in volume takes place, and in my invention it is this expansionwhich is operative to break the adhesion between the walls of the trayand the ice block.

Accordingly, it is an object of my invention to provide a new andimproved arrangement for household refrigerators in which freezing traysare removably supported within a freezing compartment so as tofacilitate freezing from the top or exposed surface of the waterdownward.

It is another object of my invention to provide a freezing compartmentof a household refrigerator with removable freezing tray supportingelements whereby if maximum ice production is not desired, theindividual trays together with their supports may be removed from thecompartment.

Further objects and advantages of my invention will become apparent asthe following description proceeds, and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

In carrying out the objects of my invention, 1 mount the freezing traysimmediately below a horizontal refrigerated wall. The trays aresupported from this wall by removable members of a material of low heatconductivity for minimizing transfer of heat from the trays themselves.Accordingly, heat is removed from the water in the trays primarily fromthe top surface thereof, and the water freezes primarily from the topdownwardly.

For a better understanding of my invention, reference may be had to theaccompanying drawings in which Fig. 1 is a fragmentary front view of thetop portion of a household refrigerator cabinet with a portion of thedoor cut away so as to show the interior arrangement; Fig. 2 is across-sectional view along the line 22 of Fig. 1; 1 1g. 3 shows a typeof freezing tray which may be utilized in conjunction with my invention;and Figs. 4, 5 and 6 are cross sections through one of the receptaclesor molds of a freezing tray, illustrating stages in the freezing of iceblocks.

In Fig. 1, I have shown the upper portion of a household refrigeratorhaving a cabinet 1 which is provided with a door 2 hinged for openingmovement so as to provide access to the interior portions of therefrigerator cabinet. The interior portion of the refrigerator cabinet 1includes a freezing compartment 3 which is defined by an inner linerelement 4. This freezing compartment has a top wall 5 which is disposedin a substantially horizontal plane. Heat is extracted from the freezingcompartment 3 through refrigerant tubing 6 which is mounted in heatexchange relationship upon the upper or unexposed surface of the topwall 5. The tubing 6 is supplied with refrigerant by a conventionalcondensing unit (not shown).

The temperature of the wall 5 and the temperature within the freezingcompartment 3 is maintained at a point substantially below the freezingpoint of water during normal operation of the refrigerator. On the loweror exposed surface of the top wall 5, I have mounted a plurality ofchannels or tracks 7 which serve as supporting guides for racks 8 whichin turn support freezing trays 9 in a horizontal position below andspaced from the top wall 5 in a manner to be described below.

Fig. 2 shows the manner in which the channels or tracks 7 are secured tothe top wall 5 of the freezing compartment. In a preferred form of myinvention, the channels or tracks 7 are secured in place by means of aplurality of screws 10. Obviously, any other satisfactory method, suchas brazing or welding, could be employed to secure the channels ortracks in position.

Referring again to Fig. 1, the channels or tracks 7 provide a trackwaywhich is adapted to receive upper flange portions 11 formed on the racks8. The flanges 11 are therefore adapted to have a sliding engagementwith the channels 7. The lower portions of the racks 8 are provided withlaterally extending flanges 12 which in turn serve as supportingsurfaces for the freezing trays 9. This arrangement permits the freezingtrays 9 to be supported in a horizontal position a short distance belowthe lower or exposed surface of the top wall 5. By virtue of the factthat this top wall 5 is refrigerated, the lowest temperatures Within thecompartment 3 exist adjacent the lower or exposed surface of this wall.In other words, with the trays 9 in position as shown in Fig. l, atemperature gradient will exist in the air surrounding the trays suchthat the top or exposed surface of the water within the tray will loseits heat more rapidly than the water in the bottom of the tray. Thisheat loss will be accomplished primarily by radiation from the top orexposed surface of the water. It is apparent, then, that the freezing ofthe water within the tray will proceed from the top downward. This,however, will only be true so long as there is no direct heat-conductionpath existing between the tray 9 and the top wall 5. If such a heatconduction path did exist, it is obvious that the water in the bottomportions of the tray 9 would lose its heat rapidly by conduction, andthe freezing process would proceed from the walls and bottom of the traytoward the center and top of the body of water. In order to prevent thisresult, the supporting racks 8 which cooperate with the channels 7 tosuspend the freezing trays 9 in position are formed of a material of lowheat conductivity. In practice I have found that polystyrene serves thispurpose very well, but it is obvious that other plastics and othermaterials of low heat conductivity could be employed for the racks 8.

In Fig. 3, I have shown a freezing tray 9 which I utilize in myinvention. This tray 9 includes a plurality of individual icereceptacles or molds 13. These receptacles or molds 13 have ahemispherical shape, but the application of my invention is not limitedto receptacles of this particular configuration; for example, I haveemployed trays having receptacles of truncated cone cross section. Theupper portion of the tray 9 is provided with outwardly extending flangesor lips 14 which, when the tray is in position within the freezingcompartment 3 as illustrated in Fig. 1, rest upon the lower flanges 12of the supporting racks 8. I have further found that the tray 9 can beconveniently formed of a plastic material although 1 do not wish to solimit my invention since I have found that a metal tray, such as brightaluminum, will atso function satisfactorily.

In Figs. 4, 5, and 6, I have illustrated the manner in which thefreezing process facilitated by my invention proceeds within a mold orreceptacle of the freezing tray 9. The particular mold has been filledwith water and has been in position under the top wall of the freezingcompartment for a short period of time in the stage illustrated in Fig.4. During this time the upper portions of the water in the mold havelost heat by radiation from the top surface to the wall 5, and, sincethis heat loss occurs at a rate much faster than any loss from thebottom portions of the water through the tray 9, a much thicker layer ofice 15 is formed along the top surface of the water in the receptaclethan the layer 16 adjacent the bottom surface of the receptacle.

As the freezing process continues, the water 17 trapped within thesurrounding shell of ice expands, and ultimately the pressure exerted bythe freezing Water causes a rupture of the surrounding ice. Since thelayer 16 is much thinner than the layer 15 along the upper region of thereceptacle, the rupture naturally occurs somewhere along the layer 16 atthe bottom portion of the tray. This causes a pressure to be exertedforcing the partially frozen ice block upwardly from the bottom of thereceptacle and causing a release of the ice block from the wall of thereceptacle. The water passing through the rupture refreezes, causing aprojection or bump 18 in the area of the rupture. The ice block at thisstage in the freezing process is illustrated generally in Fig. 5. It canbe seen from Fig. 5 that the aforementioned rupture and refreezing,again trapping the body of water 17, has resulted in the projection 18forcing upward movement of the ice block relative to the adjacent wallof the receptacle.

As the freezing process continues, the trapped water 17 in the partiallyfrozen block illustrated in Fig. 5 expands, and when the pressurebecomes sufficiently great, it causes an additional rupture of the iceblock. This rupture will normally occur in the general region of theinitial rupture since the ice layer has been weakened at this point.Ultimately the entire ice block will be frozen, in the stage illustratedin Fig. 6, the ice block in this stage being, because of the upwardforce previously exerted, substantially free of adhesion to the wall ofthe receptacle. While the freezing process has been illustrated withonly two intermediate stages, it will be appreciated that, in actualoperation, there may be a substantial num ber of ruptures andrefreezings, each effecting an upward movement of the ice block. Releaseof ice blocks is not an instantaneous process but occurs intermittentlyas pressure is periodically released by fracture of the ice walls. Hencethe ice block is released and forced upwardly a number of times duringthe completion of the freezing process. After the ice block has beencompletely frozen, as illustrated in Fig. 6, manual force may beexerted, if necessary, against the ice block adjacent the outer edgethereof, as indicated at 19, so as to make the diametrically oppositeportion 20 thereof project above the top of the tray for easy removal ofthe ice block.

In summary, it can be seen that I have provided a refrigerationapparatus with a freezing tray arrangement in which the release of iceblocks from the trays is facilitated by the actual freezing process.This I have accomplished by removably mounting the ice trays in ahorizontal position slightly below a refrigerated wall, and

supporting them by removable supports formed of a material of low heatconductivity. In such an arrangement there is no direct heat conductionpath between the tray itself and the refrigerated wall, and thereforethe water within the tray freezes in a progressive manner primarily fromthe top downward. It is also possible for the user to remove both thetrays and supports when ice production is not desired.

While I have shown a specific embodiment of my invention applied to arefrigerator having a freezing compartment, it is to be understood thatthe invention could be employed equally well in a refrigerator having nofreezing compartment as such but which utilizes a horizontal plate typeevaporator. I do not therefore wish my invention to be limited to thespecific construction shown and described, and I intend, by the appendedclaims, to cover all modifications within the spirit and scope of myinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a refrigerator cabinet the combination of a freezing compartmentdisposed within said cabinet and having a horizontally disposed top wallportion, said top wall portion having an upper surface and a lowersurface, refrigerant tubing mounted in heat exchange relationship withsaid upper surface of said top wall portion for cooling said top wallportion, a freezing tray removably supported in a horizontal positionwithin said freezing compartment below and in closely spacedrelationship with said lower surface of said top wall portion, andsupports formed of material of low heat conductivity for supporting saidtray from said top wall portion, said supports being removably mountedon said top wall portion.

2. In a refrigerator cabinet the combination as set forth in claim 1 inwhich the removable supports are formed of a plastic material of lowheat conductivity.

3. In a cabinet for refrigerators and the like, the combination of afreezing compartment disposed within said cabinet and having ahorizontally disposed top wall portion, said top wall portion having anupper surface and a lower surface, refrigerant tubing mounted in heatexchange relationship with said upper surface for cooling said top wallportion and a plurality of channels secured in a spaced parallelhorizontal position to said lower surface of said top wall portion, eachof said channels forming a trackway, and a plurality of racks formed ofmaterial of low heat conductivity having upper and lower flangeportions, said upper flange portions having sliding engagement with saidtrackways of said channels so as to removably support said racks, saidlower flange portions engaging at least one freezing tray for removablysupporting said tray below and in closely spaced relationship with saidtop wall portion.

References Cited in the file of this patent UNITED STATES PATENTS1,868,070 Newman July 19, 1932 1,898,706 Allyne Feb. 21, 1933 1,973,033Ashbaugh Sept. 11, 1934 2,037,417 Hull Apr. 14, 1936 2,217,681 JenningsOct. 15, 1940 2,218,724 Rudd Oct. 22, 1940 2,297,581 Peltier Sept. 29,1942 2,302,044 Mochel Nov. 17, 1942 2,322,626 Gerhard June 22, 19432,438,466 Tobey Mar. 23, 1948 2,457,009 Tanner Dec. 21, 1948 2,469,067Follin May 3, 1949 2,516,586 Peltier July 25, 1950

